Many inks used in the printing industry tend to have volatile organic compounds used either as the medium for dissolving dyes or as a coating aid. This requires the use of specialised mixing or handling procedures and usually some degree of flame-proofing during application.
Legislation in many countries now limits the amount of volatile organic compounds emitted to air, requiring expensive treatment to either condense these compounds for recycling/disposal or to incinerate the vapours.
Inks containing volatile organic solvents and aqueous based inks commonly use hot air drying techniques.
JP-A-1301772 describes a water-based gold pigment ink comprising a brass and/or copper powder pigment, a dispersant, water and a particular aromatic amine. The amine is believed to suppress the oxidation of the metal powder pigments thereby preventing colour change of the ink over time.
Use of mica-based gold coloured pigment is featured in the paint industry (e.g. JP-A-56129269, JP-A-87021385 and JP-A-55082170).